1. Field of the Invention
The subject matter disclosed generally relates to the field of semiconductor lasers.
2. Background Information
Semiconductor lasers are used in a variety of system applications. For example, laser diodes are commonly used as a light source in fiber optic communication systems. It is sometimes desirable to use very high powered laser diodes. For example, Erbium-doped fiber optic amplifiers and Raman fiberoptic amplifiers require pumping by a high powered laser. The pumping laser must emit a beam of high optical quality in order to be efficiently coupled to the fiber core. Because of efficiency, compactness and other factors it is desirable to pump the amplifier with a laser diode. Unfortunately, laser diodes with high quality beams typically have an upper power limit of approximately 0.5 watt, whereas fiber optic amplifiers may require 2 watts or more.
Referring to FIG. 1, the power of a laser diode 1 can be increased by widening the pumped stripe 2 of the diode 1. Widening the pumped stripe 2 reduces the optical power density and resultant heat within the diode 1.
It has been found that at high power densities, the light generated in a widened laser diode will “self-focus” into filaments across the length of stripe 2. This self-focus effect creates an output beam with intensity spikes as shown in FIG. 1. The quality of such an output is unacceptable for most photonic applications. It would be desirable to provide a high powered laser diode that emits a high quality laser beam.